FXUS62 KFFC 250300 AAA
AFDFFC
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1000 PM EST THU DEC 24 2009
.UPDATE...
MADE SOME ADJUSTMENTS TO RAISE OVERNIGHT MIN TEMPERATURES ACROSS
MUCH OF NORTH AND WEST CENTRAL GEORGIA AS CURRENT TEMPERATURES ARE
NEARING WET BULB TEMPERATURES AT MANY LOCATIONS...AND WITH WARM
ADVECTION OVERNIGHT...DO NOT ANTICIPATE SIGNIFICANT COOLING EVEN
AFTER ONSET OF HEAVIER RAINFALL. ISOLATED SEVERE THUNDERSTORMS
STILL POSSIBLE GENERALLY SOUTH OF INTERSTATE 20 LATER TONIGHT AS
STRONG LOW-LEVEL JET MOVES ACROSS THE STATE. MOST UNSTABLE CAPES
OF 100-300 J/KG COMBINED WITH STRONG DEEP LAYER AND LOW-LEVEL
SHEAR SHOULD BE SUFFICIENT FOR SOME DAMAGING WIND GUSTS AS WELL AS
THE POSSIBILITY OF ISOLATED TORNADOES. HIGH WIND WARNING STILL
LOOKS ON TRACK FOR NORTHERN COUNTIES...A FEW LOCATIONS HAVE
ALREADY REPORTED GUSTS TO 40 MPH...AND THIS SHOULD ONLY INCREASE
OVERNIGHT AS 80 KT LOW-LEVEL JET APPROACHES. UPDATED GRIDS AND
ZONE FORECAST HAVE BEEN SENT.
MSR
&&
.PREV DISCUSSION... /ISSUED 345 PM EST THU DEC 24 2009/
SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
CURRENT RADAR LOOP SHOWS LIGHT RAIN BEGINNING TO MOVE INTO WEST
GEORGIA. THIS RAIN IS THE FIRST BATCH THAT IS WELL OUT AHEAD OF THE
FRONT. THIS FIRST AREA IS VERY STABLE WITH VERY LITTLE INSTABILITY
ASSOCIATED WITH IT. THE MAIN AREA OF INSTABILITY IS ASSOCIATED WITH
THE FRONT WHICH IS MOVING INTO WESTERN MISSISSIPPI AT THE MOMENT.
THE WARM FRONT IS STILL HANGING AROUND THE GULF COAST AND IS
EXPECTED TO MOVE SLIGHTLY NORTHWARD INTO SOUTH GA TONIGHT. THIS WILL
PUT SOUTHERN PORTIONS OF THE STATE IN THE WARM SECTOR OF THIS SYSTEM
WITH INSTABILITIES INCREASING OVER NIGHT AS WELL. LOOKS LIKE THE
BEST PLACE FOR SEVERE STORMS WILL BE SOUTH OF A COLUMBUS TO VIDALIA
LINE TONIGHT THROUGH FRIDAY MORNING. THERE IS A VERY STRONG LOW
LEVEL JET ASSOCIATED WITH THIS SYSTEM THAT WILL HELP TO BRING
INCREASED MOISTURE OFF THE GULF/ATLANTIC TONIGHT. AS THE ATMOSPHERE
MOISTENS AND DESTABILIZES THUNDERSTORM DEVELOPMENT WILL BECOME MORE
LIKELY ESPECIALLY AFTER 03Z-06Z. THIS LOW LEVEL JET WILL ALSO HELP
TO ENHANCE VERTICAL SHEAR WHICH WILL BE SUPPORTIVE OF A FEW ROTATING
STORMS AND AN ISOLATED TORNADO OR TWO. CURRENTLY THE MODELS ARE
STILL SHOWING 1 TO 1.5 INCHES OF PRECIPITATION WITH THIS SYSTEM SO
WE SHOULD NOT HAVE TO DEAL WITH ANY MAJOR FLOODING. CONTINUE MINOR
FLOODING ESPECIALLY ACROSS CENTRAL GEORGIA SHOULD BE ALL WE SEE.
LAST ITEM TO ADDRESS ARE THE WINDS. GUIDANCE INCREASES WINDS ACROSS
MOST OF THE AREA INTO THE 20 TO 25KT RANGE WITH GUST IN THE 30S. IM
SURE WITH THESE NUMBERS WE WILL SEE EVEN HIGHER GUST IN THE HIGHER
ELEVATIONS OF THE N GA MOUNTAINS. HAVE DECIDED TO ISSUE A HIGH WIND
WARNING BEGINNING AT 00Z FRI AND CONTINUING THOUGH 12Z FRI. THE
COLD FRONT SWEEPS THROUGH THE CWA TONIGHT...AND BY 12Z- 14Z FRI
THE LAST OF THE SHOWERS WILL BE EXITING THE EASTERN PART OF THE
AREA. WRAP AROUND MOISTURE WILL RETURN TO EXTREME NORTH GA
BRINGING CLOUDY SKIES...ELSEWHERE SKIES WILL BE CLEARING DURING
THE DAY FRIDAY. IT WILL REMAIN A BIT WINDY BUT LOOKS LIKE AN
ADVISORY WILL NOT BE NEEDED AT THE MOMENT.
01
LONG TERM /SUNDAY THROUGH THURSDAY/...
THROUGH AT LEAST TUESDAY THE LARGE H5 LOW OVER THE MIDWEST WILL TAKE
ITS TIME FILLING AND LIFTING NORTHEAST. THIS WILL KEEP THE CWA IN A
DRY NORTHWEST FLOW. BY TUESDAY AN H5 TROUGH MOVES OUT OF THE PACIFIC
AND INTO THE SOUTHERN ROCKIES...THEN INTO THE SOUTHERN PLAINS ON
WEDNESDAY. GFS AND ECMWF DIFFER ON LOCATION AND STRENGTH OF THE
MOISTURE ASSOCIATED WITH THIS FEATURE. GFS WEAKENS THE FIRST WAVE BY
THE TIME IT GETS HERE WITH ANOTHER WAVE DEEPENING OVER THE DESERT
SOUTHWEST. ECMWF STRENGTHENS THE 1ST S/W AND SPREADS MOISTURE OVER
THE CWA ON WEDNESDAY. WILL GO WITH SLIGHT CHANCE POPS WEDNESDAY.
TEMPS WILL REMAIN SEASONAL THROUGH THE LONG TERM.
01
AVIATION...
-RA HAS MOVED INTO THE TAF SITES. GENERALLY MVFR CONDITIONS ACROSS
THE AREA...WITH THE EXPECTATION OF CONDITIONS LOWERING TO IFR. WINDS
WILL INCREASE OVERNIGHT WITH GUSTS 28 TO 30 KTS...AND THEN BEGIN TO
SUBSIDE LATE MORNING. EXPECT A WIND SHIFT FROM E TO SW TOMORROW
MORNING...AROUND 14Z AT THE ATL METRO SITES. RA TO CONTINUE THROUGH
OVERNIGHT AND INSTABILITIES SUPPORT THE POSSIBILITY OF TS AT THE
SOUTHERN TAF SITES...CSG AND MCN...SO WILL INCLUDE CB FOR NOW. BIG
DIFFERENCE BETWEEN NAM AND GFS TOMORROW EVENING WITH GFS SHOWING
SCT250 CEILINGS AND NAM INDICATING OVC025. PLAN ON LEANING MORE
TOWARD THE NAM SIDE AND SHOWING A GRADUAL INCREASE IN CEILINGS
TOMORROW AND TOMORROW NIGHT.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 43 54 30 53 31 / 100 50 0 5 10
ATLANTA 44 51 28 50 35 / 100 30 0 5 10
BLAIRSVILLE 39 44 25 48 23 / 100 40 5 5 10
CARTERSVILLE 44 51 26 50 29 / 100 20 0 5 10
COLUMBUS 49 56 30 54 35 / 100 10 0 5 10
GAINESVILLE 41 47 27 51 33 / 100 40 0 5 10
MACON 51 58 29 55 34 / 100 40 0 5 10
ROME 45 50 30 52 30 / 100 10 5 5 20
PEACHTREE CITY 45 54 27 52 26 / 100 20 0 5 10
VIDALIA 54 65 33 55 32 / 100 70 0 0 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 AM EST FRIDAY FOR THE FOLLOWING ZONES:
BALDWIN...BANKS...BARROW...BIBB...BLECKLEY...BUTTS...CARROLL...
CHATTAHOOCHEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...
CRISP...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...FAYETTE...
FORSYTH...GLASCOCK...GREENE...GWINNETT...HALL...HANCOCK...
HARALSON...HARRIS...HEARD...HENRY...HOUSTON...JACKSON...JASPER...
JEFFERSON...JOHNSON...JONES...LAMAR...LAURENS...MACON...
MADISON...MARION...MERIWETHER...MONROE...MONTGOMERY...MORGAN...
MUSCOGEE...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...
PAULDING...PEACH...PIKE...POLK...PULASKI...PUTNAM...ROCKDALE...
SCHLEY...SOUTH FULTON...SPALDING...STEWART...SUMTER...TALBOT...
TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TREUTLEN...TROUP...
TWIGGS...UPSON...WALTON...WARREN...WASHINGTON...WEBSTER...
WHEELER...WILCOX...WILKES...WILKINSON.
HIGH WIND WARNING UNTIL 7 AM EST FRIDAY FOR THE FOLLOWING ZONES:
BARTOW...CATOOSA...CHATTOOGA...CHEROKEE...DADE...DAWSON...
FANNIN...FLOYD...GILMER...GORDON...LUMPKIN...MURRAY...PICKENS...
TOWNS...UNION...WALKER...WHITE...WHITFIELD.
&&
$$
